Embodiments of the present invention relate generally to laser shock peening and more particularly to a method for determining all accessible angles to a region on an object that is to be laser shock peened.
Laser shock peening (LSP) is a surface treatment technique that is applied to improve fatigue performance of metallic components. Laser shock peening or laser shock processing, is a process for producing a region of deep compressive residual stresses on a surface area of an object. Typically, LSP uses one or more radiation pulses from high power pulsed lasers to produce an intense shock wave at the surface of the object. In other words, in LSP, a pulsed laser beam from a laser beam source is generally utilized to produce a strong localized compressive force on a portion of a surface of the object by impinging a laser beam on a point, the high energy laser beam produces a strong localized compressive force by an instantaneous ablation or vaporization of a thin layer of the surface or of a coating (such as tape or paint) on that surface.
As will be appreciated, laser shock peening requires access to a region on the object. The object may include a blisk for example. Also the blisk may be a single stage blisk or a multi-stage blisk. It may be desirable to access a region on a blade of the blisk. However, there are many obstacles that may interfere with access to the region on the blade that is to be laser shock peened. Unfortunately, the amount of energy in the laser beam may render the entire blisk unusable due to inaccessibility to the specified region on the blade. Further, an irregular geometry and clocking of blades in the blisk make it difficult to determine a feasible approach angle that also matches the physics requirement of the LSP.
Currently, commercial software solutions are available to plan a collision free path or to evaluate a path that has been developed earlier.
Unfortunately, these software solutions are not capable of handling multiple tools and/or 6+ axes. Furthermore, collision free paths can be evaluated through visual inspection only after a full path has been developed. More particularly, analysis for access is performed only after the path has been developed. This analysis requires an iterative, manual and laborious method to determine a solution for accessibility to the region of interest. Moreover, these software solutions do not allow for preplanning of accessibility for LSP and a choice of an optimal feasible solution. Several other software routines are available that facilitate determination of accessibility to a point or a set of objects from a specific angle. However, these approaches cannot be used with LSP, as LSP cannot work with a static approach angle.
It is therefore desirable to develop a method for determining all accessible angles to a region of interest in an object that is to be laser shock peened without developing a full path.